DOCSLIB.ORG

Relation Between Surface Structural and Chemical Properties of Platinum Nanoparticles and Their Catalytic Activity in the Decomposition of Hydrogen Peroxide

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Relation Between Surface Structural and Chemical Properties of Platinum Nanoparticles and Their Catalytic Activity in the Decomposition of Hydrogen Peroxide Relation Between Surface Structural And Chemical Properties Of Platinum Nanoparticles And Their Catalytic Activity In The Decomposition Of Hydrogen Peroxide Rui Filipe Serra Maia Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy In Geosciences F. Marc Michel, Chair J. Donald Rimstidt Christopher Winkler Mitsuhiro Murayama August 6th, 2018 Blacksburg, Virginia Keywords: Catalysis, Hydrogen Peroxide Decomposition, Metal Nanoparticles, Metal Nanocatalysts, Crystal Structure, Surface Chemistry, H2O2 decomposition Mechanism, H2O2 Decomposition Kinetics, Catalytic Activity of Platinum Relation Between Surface Structural And Chemical Properties Of Platinum Nanoparticles And Their Catalytic Activity In The Decomposition Of Hydrogen Peroxide Rui Filipe Serra Maia ABSTRACT The disproportionation of H2O2 to H2O and molecular O2 catalyzed by platinum nanocatalysts is technologically very important in several energy conversion technologies, such as steam propellant thrust applications and hydrogen fuel cells. However, the mechanism of H2O2 decomposition on platinum has been unresolved for more than 100 years and the kinetics of this reaction were poorly understood. Our goal was to quantify the effect of reaction conditions and catalyst properties on the decomposition of H2O2 by platinum nanocatalysts and determine the mechanism and rate-limiting step of the reaction. To this end, we have characterized two commercial platinum nanocatalysts, known as platinum black and platinum nanopowder, and studied the effect of different reaction conditions on their rates of H2O2 decomposition. These samples have different particle size and surface chemisorbed oxygen abundance, which were varied further by pretreating both samples at variable conditions. The rate of H2O2 decomposition was studied systematically as a function of H2O2 concentration, pH, temperature, particle size and surface chemisorbed oxygen abundance. The mechanism of H2O2 decomposition on platinum proceeds via two cyclic oxidation- reduction steps. Step 1 is the rate limiting step of the reaction. Step 1: 푃푡 + 퐻푂 → 퐻푂 + 푃푡(푂). Step 2: 푃푡(푂) + 퐻푂 → 푃푡 + 푂 + 퐻푂. Overall: 2 퐻푂 → 푂 + st 2 퐻푂. The decomposition of H2O2 on platinum follows 1 order kinetics in terms of H2O2 concentration. The effect of pH is small, yet statistically significant. The rate constant of step 2 is 13 times higher than that of step 1. Incorporation of chemisorbed oxygen at the nanocatalyst surface resulted in higher initial rate of H2O2 decomposition because more sites initiate their cyclic process in the faster step of the reaction. Particle size does not affect the kinetics of the reaction. This new molecular-scale understanding of the decomposition of H2O2 by platinum is expected to help advance many energy technologies that depend on the rate of H2O2 decomposition on nanocatalysts of platinum and other metals. Relation Between Surface Structural And Chemical Properties Of Platinum Nanoparticles And Their Catalytic Activity In The Decomposition Of Hydrogen Peroxide Rui Filipe Serra Maia GENERAL AUDIENCE ABSTRACT Platinum nanomaterials are indispensable to catalyze a variety of industrial and technological processes ranging from catalytic conversion of carbon monoxide (CO), hydrocarbons, and nitrogen oxides (NOx) in modern automobiles to energy production by hydrogen fuel cells and thrust generation in steam propellers. These technological innovations have a tremendous impact in modern society, including the areas of transportation, energy supply, soil and water quality, environmental remediation and global climate change. The decomposition of hydrogen peroxide (H2O2) to water (H2O) and oxygen (O2) on platinum nanomaterials is of particular importance because it affects the efficacy of many technological applications, such as hydrogen peroxide steam propellers and hydrogen fuel cells. However, the reaction pathway and kinetics of H2O2 decomposition on platinum were only partly understood. My goal was to understand how the reaction conditions and the nanocatalyst properties control the mechanism and kinetics of platinum-catalyzed hydrogen peroxide decomposition. To do that we characterized the atomic scale structural and chemical properties of two different platinum nanocatalysts, known as platinum black and platinum nanopowder and evaluated the effect of their properties in their catalytic activity. Our characterization studies were used to understand the reactivity of these two platinum nanocatalysts in the decomposition of H2O2, which we evaluated separately in laboratory studies. Establishing relationships between the catalyst properties and their activity, as we have done in this work for platinum nanocatalysts in the decomposition of hydrogen peroxide, has the potential to improve nanocatalyst design and performance for those applications. Acknowledgements After four and half years of intense work during this PhD project, writing this acknowledgement note is the finishing touch to my dissertation. These years have been a period of endless learning at a scientific and personal level, and at this moment I would like to reflect on people without whom this degree would not have been possible. I would first like to thank my outstanding advisor, Dr. F. Marc Michel. Marc is extremely insightful and the most visionary person I have ever met. No wonder he is so successful at a professional and personal level. His guidance was instrumental in our scientific achievements and I completely look forward to collaborate with him in many other projects in the future. I would also like to thank my other committee members, Dr. J. Donald Rimstidt, Dr. Christopher Winkler and Dr. Mitsuhiro Murayama for their support and scientific expertise. As Don once taught me “The reason why you should listen to your committee members is because we have done many mistakes throughout our careers, and we are here to guide you so you don’t do them yourself”. A lot of the characterization work I performed would not have been possible without the guidance and assistance of people at the NCFL, including Chris Winkler (also a member of my committee), Steve McCartney, Andrew Giordani and Jay Tuggle. Several undergraduate students worked with me in this project, particularly performing rate measurements of H2O2 decomposition. Mentoring them was an absolute privilege and has allowed me to develop mentorship skills that I hope to apply in the future as a principal investigator. In particular I want to highlight Kevin Tranhuu, Ivy Bellier and Stephen Chastka. They are extremely skilled and hardworking students. I am sure they will be very successful in their endeavors. Within the department I am sincerely thankful for the amazing faculty, students and staff I had the pleasure to spend time with during these years. In particular I want to thank iv former and present graduate students of the Michel research group, Hannah King, Aly Hoeher, Karel Kleteschka, Allie Nagurney, McNeil Bauer and Bryan Raimbault for their friendship and insightful scientific discussions. In Blacksburg (this amazing place I had the pleasure to live in for four and half years) I want to thank people that highly contributed for my happiness and well-being. In particular I want to name the folks with whom I played tennis and racquetball on a regular basis, Hannah King, McNeil Bauer, Kira Dickey, Addison Dalton and Bob Bodnar as well as the Portuguese community of Blacksburg. Thankfully the latter was only composed of a few people, so naming all of them is an easy task, but well deserved, Paulo Polanah, Rita Teixeira, Jorge Costa, João Monteiro, Iris Vilares and Alexandre Ribeiro. Our regular dinners/coffees were memorable and unique! At the family level there are really a lot of people to thank and I will never be able to thank them enough. First and foremost, my wonderful wife, Temple, who puts up with me and makes my life much funnier and a lot more meaningful (even though we can never agree on the house temperature). We have the cutest dog in the world, Rascal, an endless source of fun and joy that makes everyday a lot more entertaining. Throughout these years my in-laws have been an infinite source of support, and I am very thankful for all the weekends and vacation Temple, Rascal and I have spent with them. Last but not least, my parents, siblings, cousins, nephews, nieces and other relatives. I am very proud of my parents, Rosa and Manuel Augusto, and I will be always amazed how two parents with only 4th grade of elementary school of education level, born and raised in a small and relatively isolated village in Portugal, Covelas in the municipality of Trofa, had the wisdom to guide all their five children (my four siblings and I) to obtain college degrees. Their hard work was an inspiration to always aim higher and better, without ever forgetting honesty, fairness and gratitude to people around us that in one way or another contributed to our achievements. On that note, my siblings, Armindo, Emília, Lino and João (all older than me) truly were an inspiration. For all these years they were a source of priceless help (of all kinds), without ever expecting any kind of retribution. If I made it to a PhD at this great University, Virginia Tech, I owe that to my family almost entirely. v Table of Contents ABSTRACT .............................................................................................................................................
Load more

Recommended publications
  • Thermochemical Conversion of Biomass in the Presence of Molten Alkali-Metal Carbonates Under Reducing Environments of N2 and CO2
    energies Article Thermochemical Conversion of Biomass in the Presence of Molten Alkali-Metal Carbonates under Reducing Environments of N2 and CO2 Tahereh Jalalabadi, Behdad Moghtaderi and Jessica Allen * School of Chemical Engineering, University of Newcastle, Callaghan, NSW 2308, Australia; [email protected] (T.J.); [email protected] (B.M.) * Correspondence: [email protected]; Tel.: +612-40-339-359 Received: 15 September 2020; Accepted: 12 October 2020; Published: 15 October 2020 Abstract: The impact of N2 and CO2 atmospheres on the interaction between Eucalyptus pilularis biomass and a ternary molten carbonate eutectic (Li2CO3: Na2CO3:K2CO3) has been investigated at 600 ◦C and 900 ◦C. For lower temperature conversion under CO2, prevention of volatile release in the eutectic treated biomass is slightly higher than under N2 injection; however, similar bubble-shaped morphology of the remnant char is observed under both carrier gases. By increasing the temperature to 900 ◦C under CO2, the reverse Boudouard reaction begins to consume carbon fuel, while molten carbonate gasification also accelerates the reaction to a lower temperature set point (shifted from ~735 ◦C to ~640 ◦C). The mass loss of carbonate under CO2 and N2 at 900 ◦C is 0 (negligible) and 18 wt.%, respectively. In the absence of carbon particles, the decomposition of carbonate to M2O (l) and CO2 (g), as well as molten salt vaporization, are the sole potential routes of weight loss in an inert gas. Previous observations of biomass and eutectic mixture thermochemical conversion under N2 have suggested carbon/carbonate gasification is dominant at elevated temperatures, with production of CO expected.
    [Show full text]
  • Synthesis and Exploratory Deposition Studies of Isotetrasilane and Reactive Intermediates for Epitaxial Silicon
    This is an open access article published under a Creative Commons Non-Commercial No Derivative Works (CC-BY-NC-ND) Attribution License, which permits copying and redistribution of the article, and creation of adaptations, all for non-commercial purposes. Article Cite This: Inorg. Chem. 2019, 58, 3050−3057 pubs.acs.org/IC Synthesis and Exploratory Deposition Studies of Isotetrasilane and Reactive Intermediates for Epitaxial Silicon ,† † † † ‡ Barry Arkles,* Youlin Pan, Fernando Jove, Jonathan Goff, and Alain Kaloyeros † Gelest Inc., Morrisville, Pennsylvania 19067, United States ‡ SUNY Polytechnic Institute, Albany, New York 12203, United States ABSTRACT: A synthetic method is presented for the production of isotetrasilane, a higher order perhydridosilane, with the purity and volume necessary for use in extensive studies of the chemical vapor deposition (CVD) of epitaxial silicon (e-Si) thin films. The chemical characteristics, thermodynamic properties, and epitaxial film growth of isotetrasilane are compared with those of other perhydridosi- lanes. A film-growth mechanism distinct from linear perhy- ≤ dridosilanes H(SiH2)nH, where n 4, is reported. Preliminary findings are summarized for CVD of both unstrained e-Si and strained e-Si doped with germanium (Ge) and carbon (C) employing isotetrasilane as the source precursor at temper- atures of 500−550 °C. The results suggest that bis- (trihydridosilyl)silylene is the likely deposition intermediate under processing conditions in which gas-phase depletion reactions are not observed. ■ INTRODUCTION such as trisilane. However, the latter was observed to generate As emerging integrated chip (IC) and solar cell technologies gas-phase particles (silicon hydride clusters) due to its much continue to reduce individual device feature sizes, chemical higher reactivity and lower dissociation energy in comparison 5 vapor deposition (CVD) of epitaxial silicon (e-Si) has emerged to silane and disilane.
    [Show full text]
  • Kinetics of the Uncatalyzed, Alkaline Decomposition of Hydrogen Peroxide Trice Walter Haas Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1960 Kinetics of the uncatalyzed, alkaline decomposition of hydrogen peroxide Trice Walter Haas Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Physical Chemistry Commons Recommended Citation Haas, Trice Walter, "Kinetics of the uncatalyzed, alkaline decomposition of hydrogen peroxide " (1960). Retrospective Theses and Dissertations. 2645. https://lib.dr.iastate.edu/rtd/2645 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. KINETICS OF THE UN CATALYZED, ALKALINE DECOMPOSITION OF HYDROC-EN PEROXIDE by Trice Walter Haas A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subject: Physical Chemistry Approved: Signature was redacted for privacy. In Charge of Major Work Signature was redacted for privacy. Head of Major Department Signature was redacted for privacy. Iowa State University Of Science and Technology Ames, Iowa I960 il TABLE OP CONTENTS Page I. INTRODUCTION 1 II. EXPERIMENTAL 8 A. Apparatus 8 B. Quenching Technique 9 C. Analytical Techniques 10 D. Purification Methods 13 III. RESULTS AND DISCUSSION 20 A. The Homogeneous, Uncatalyzed Decomposition 20 1» General 20 2. Impurity effects 20 3* Surface effects 22 L Effect of light 27 5. Inert ions 28 6. Experimental results and discussion 29 7* Sources of error $1 B.
    [Show full text]
  • An Example of Decomposition Reaction
    An Example Of Decomposition Reaction Wes remains unhorsed after Thatch stiffen tantalisingly or holings any Tissot. Certificated Wye sometimes deoxygenated any layabout chats botanically. Rab sicks sunnily if dirtier Apostolos unthaw or philter. It catches fire or exothermic reaction is described by energy input it later as decomposition of an reaction to logged in the case for the number of food. A decomposition reaction produces multiple products from every single reactant Combustion reactions are the combination of some compound whereas oxygen would make oxides of cotton other elements as products although nitrogen atoms react to make N 2. You dive into silver metal is an example of reaction! In chemical equations so how data for the example of the iupac name and alkynes: when carbonates and vinegar stoichiometry and. CBSE 10th Board Exam 2021 Check Revision Notes for. Hydrogen peroxide decomposes to an example of decomposition reaction below contains the first game code required for disproving the products? The reactant is decomposed by energy sources such as though, Upper bound, it decomposes to give potassium chloride and oxygen. Stoichiometry Lab Answer Keyyour experiment. Is an example reaction! Do not want to delete this image? Chemical decomposition Wikipedia. Worksheet 3 Decomposition Reactions ScienceGeeknet. In order for a chemical equation to be properly balanced, make sure you use real salt, while in a combination reaction two or more substances combine to form one single substance. Make sure equation is balanced. An overturn of decomposition reaction is decomposition of lead nitrate to instead lead oxide, silver bromide to gets decomposed. Set solution being a wet acid.
    [Show full text]
  • Performance Asymmetric Supercapacitors Stack Based on Nickel Hexacyanoferrate-Derived Ni(OH)
    www.nature.com/scientificreports OPEN Fabrication of 9.6 V High- performance Asymmetric Supercapacitors Stack Based on Received: 17 August 2018 Accepted: 10 December 2018 Nickel Hexacyanoferrate-derived Published: xx xx xxxx Ni(OH)2 Nanosheets and Bio- derived Activated Carbon Subramani Kaipannan1,2 & Sathish Marappan1,2 Hydrated Ni(OH)2 and activated carbon based electrodes are widely used in electrochemical applications. Here we report the fabrication of symmetric supercapacitors using Ni(OH)2 nanosheets and activated carbon as positive and negative electrodes in aqueous electrolyte, respectively. The asymmetric supercapacitors stack connected in series exhibited a stable device voltage of 9.6 V and delivered a stored high energy and power of 30 mWh and 1632 mW, respectively. The fabricated device shows an excellent electrochemical stability and high retention of 81% initial capacitance after 100,000 charge-discharges cycling at high charging current of 500 mA. The positive electrode material Ni(OH)2 nanosheets was prepared through chemical decomposition of nickel hexacyanoferrate complex. The XRD pattern revealed the high crystalline nature of Ni(OH)2 with an average crystallite size of ~10 nm. The nitrogen adsorption-desorption isotherms of Ni(OH)2 nanosheets indicate the formation of mesoporous Ni(OH)2 nanosheets. The chemical synthesis of Ni(OH)2 results the formation of hierarchical nanosheets that are randomly oriented which was confrmed by FE-SEM and HR-TEM analysis. The negative electrode, activated porous carbon (OPAA-700) was obtained from orange peel waste. The electrochemical properties of Ni(OH)2 nanosheets and OPAA-700 were studied and exhibit a high specifc capacity of 1126 C/g and high specifc capacitance of 311 F/g at current density of 2 A/g, respectively.
    [Show full text]
  • Non-Fossil Fuel Process for Production of Hydrogen and Oxygen
    United States Patent mi [in 3,802,993 von Fredersdorff, deceased et al. [45] Apr. 9, 1974 [54] NON-FOSSIL FUEL PROCESS FOR 86,248 1/1869 Phillips 423/579 PRODUCTION OF HYDROGEN AND OTHER PUBLICATIONS OXYGEN James V. Quagliano, Chemistry Second Edition, Au- [75] Inventors: Claus George von Fredersdorff, gust, 1963, Prentice-Hall Inc., pp. 108-117. deceased, late of Oak Park, 111.; by George C. von Fredersdorff, Primary Examiner—Harvey E. Behrend administrator, Des Plaines, 111. Attorney, Agent, or Firm—Molinare, Allegretti, Newitt [73] Assignee: Institute of Gas Technology, & Witcoff Chicago, 111. [22] Filed: Dec. 27, 1971 [57] ABSTRACT [21] Appl. No.. 211,960 Hydrogen and oxygen production by fissiochemical decomposition of carbon dioxide to produce carbon monoxide and oxygen, followed by subsequent separa- [52] U.S. CI 176/37, 176/39, 423/219, tion of the oxygen from the carbon monoxide, and 423/579, 423/658 production of hydrogen by the action of steam on iron [51] Int. CI G21c 9/00 at elevated temperature followed by regeneration of [58] Field of Search 176/10, 37, 38, 39, 92 R; the product iron oxide by carbon monoxide as sepa- 204/129; 423/648, 656, 657, 579, 594, 219, rated from the fissiochemical decomposition products 248; 252/301.1; 23/204, 221, 210-214 issuing from the nuclear reactor. The oxygen may be separated from the fissiochemical decomposition [56] References Cited products by the formation of metal oxide by reaction UNITED STATES PATENTS with reactive metals such as iron, chromium, manga- 2,558,756 7/1951 Jackson et al 423/579 nese and mercury.
    [Show full text]
  • Catalytic Oxidation Process for the Degradation of Synthetic Dyes: an Overview
    International Journal of Environmental Research and Public Health Review Catalytic Oxidation Process for the Degradation of Synthetic Dyes: An Overview Rahat Javaid 1,* and Umair Yaqub Qazi 2 1 Renewable Energy Research Center, Fukushima Renewable Energy Institute, National Institute of Advanced Industrial Science and Technology, AIST, 2-2-9 Machiikedai, Koriyama, Fukushima 963-0298, Japan 2 Chemistry Department, College of Science, University of Hafr Al Batin, P.O Box 1803 Hafr Al Batin 31991, Saud Arabia; [email protected] * Correspondence: [email protected] Received: 26 March 2019; Accepted: 7 June 2019; Published: 11 June 2019 Abstract: Dyes are used in various industries as coloring agents. The discharge of dyes, specifically synthetic dyes, in wastewater represents a serious environmental problem and causes public health concerns. The implementation of regulations for wastewater discharge has forced research towards either the development of new processes or the improvement of available techniques to attain efficient degradation of dyes. Catalytic oxidation is one of the advanced oxidation processes (AOPs), based on the active radicals produced during the reaction in the presence of a catalyst. This paper reviews the problems of dyes and hydroxyl radical-based oxidation processes, including Fenton’s process, non-iron metal catalysts, and the application of thin metal catalyst-coated tubular reactors in detail. In addition, the sulfate radical-based catalytic oxidation technique has also been described. This study also includes the effects of various operating parameters such as pH, temperature, the concentration of the oxidant, the initial concentration of dyes, and reaction time on the catalytic decomposition of dyes.
    [Show full text]
  • The Role of Abiotic Processes in the Formation and Degradation of Gaseous Nitrogen Compounds in the Soil
    Institut für Nutzpflanzenwissenschaften und Ressourcenschutz (INRES) Bodenwissenschaften The role of abiotic processes in the formation and degradation of gaseous nitrogen compounds in the soil Inaugural-Dissertation zur Erlangung des Grades Doktor der Agrarwissenschaften (Dr. agr.) der Landwirtschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn vorgelegt von Jannis Heil aus Essen Bonn 2015 Referent: Prof. Dr. Nicolas Brüggemann Korreferent: Prof. Dr. Wulf Amelung Tag der mündlichen Prüfung: 10.08.2015 I Contents Acknowledgements ..................................................................................................................... IV Abstract ......................................................................................................................................... V Zusammenfassung ...................................................................................................................... VII List of Figures ............................................................................................................................. IX List of Tables ............................................................................................................................... XI List of abbreviations ................................................................................................................... XII 1. Introduction .............................................................................................................................. 1 1.1. Rationale ...........................................................................................................................
    [Show full text]
  • THERMAL DECOMPOSITION and EXPLOSION of AMMONIUM PERCHLORATE and AMMONIUM PERCHLORATE PROPELLANT up to 50 KILOBARS (5.0X10' N/M2)
    NASA TECHNICAL NOTE NASA TN D-6013 cr) c- 0 liom COPY -? n Am KIR!I"D I I- 4 m 4 z THERMAL DECOMPOSITION AND EXPLOSION OF AMMONIUM PERCHLORATE AND AMMONIUM PERCHLORATE PROPELLANT UP TO 50 KILOBARS (5.0X10' N/m2) by Huns R. Voelkl Lewis Research Center Cleueland, Ohio 44135 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. SEPTEMBER 1970 TECH LIBRARY KAFB, NM - ... __ - 0132bb4 1. Report No. 2. Government Accession No. 3. Recipient's Catalog IVO. NASA TN D-6013 - -.. 4. Title and Subtitle THERMAL DECOMPOSITION AND EXPLOSION OF 5. Report Date September 1970 AMMONIUM PERCHLORATE AND AMMONIUM PERCHLORATE 6. Performing Organization Code PROPELLANT UP TO 50 KILOBARS (5. OXlO9 N/m2) 7. Author(s) 8. Performing Organization Report No. Hans R. Voelkl E-4568 10. Work Unit No. 9. Performing Organization Name- and Address 129-03 Lewis Research Center 11. Contract or Grant No. National Aeronautics and Space Administration Cleveland, Ohio 44135 13. Type of Report and Period Covered I12. Sponsoring Agency Name and Address Technical Note - National Aeronautics and Space Administration 14. Sponsoring Agency Code Washington, D. C. 20546 -. 15. Supplementary Notes L - - . - -. 16. Abstract The rates of thermal decomposition of ammonium perchlorate and an ammonium perchlorate 9 9 9 2 solid propellant at 15, 25, and 50 kilobars (1.5X10 , 2.5X10 , and 5.0XlO N/m ) pressure were studied in a cubic anvil press. The data were correlated by first order rate equations to obtain the temperature variation of the specific reaction rates and the apparent activation energies. Explosion limits of pure ammonium perchlorate are included to 30 kilobars (3.
    [Show full text]
  • Prevention Guide
    PREVENTION GUIDE FORMALDEHYDE IN THE WORKPLACE prepared by Nicole Goyer, Denis Bégin, Charles Beaudry, Michèle Bouchard, Gaétan Carrier, Jérôme Lavoué, Nolwenn Noisel et Michel Gérin—October 2006 Established in Québec since 1980, the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) is a scientific research organization known for the quality of its work and the expertise of its personnel. OUR RESEARCH IS WORKING FOR YOU! MISSION • To contribute, through research, to the prevention of industrial accidents and occupational diseases as well as to the rehabilitation of affected workers. • To offer the laboratory services and expertise necessary for the activities of the public occupational health and safety prevention network. • To disseminate knowledge, and to act as scientific benchmark and expert. Funded by the Commission de la santé et de la sécurité du travail, the IRSST has a board of directors made up of an equal number of employer and worker representatives. TO FIND OUT MORE Visit our Web site for complete up-to-date information about the IRSST.All our publications can be downloaded at no charge. www.irsst.qc.ca To obtain the latest information on the research carried out or funded by the IRSST, subscribe to Prévention au travail, the free magazine published jointly by the IRSST and the CSST. Subscription: 1-877-221-7046 Legal Deposit Bibliothèque et Archives nationales 2006 ISBN 13 : 978-2-89631-068-5 (print format) ISBN 10 : 2-89631-068-1 (print format) ISBN 13 : 978-2-89631-069-2 (PDF) ISBN 10 : 2-89631-069-X (PDF) Original Edition:ISBN 10: 2-89631-066-5 ISSN: 0820-8395 IRSST - Communications Division 505, boul.
    [Show full text]
  • Physical and Chemical Change 13.1
    Physical and chemical CHAPTER 13. PHYSICAL AND CHEMICAL CHANGE change 13 Introduction ESADS Matter is all around us. The desks we sit at, the air we breathe and the water we drink are all examples of matter. But matter doesn’t always stay the same. It can change in many different ways. In this chapter, we are going to take a closer look at physical and chemical changes that occur in matter. See introductory video: ( Video: VPber at www.everythingscience.co.za) Physical changes in matter ESADT A physical change is one where the particles of the substances that are involved in the change are not broken up in any way. When water is heated for example, the temperature and energy of the water molecules increases and the liquid water evaporates to form water vapour. When this happens, some kind of change has taken place, but the molecular structure of the water has not changed. This is an example of a physical change. All changes in state are physical changes. H O(ℓ) H O (g) 2 → 2 Conduction (the transfer of energy through a material) is another example of a physical change. As energy is transferred from one material to another, the energy of each material is changed, but not its chemical makeup. Dissolving one substance in another is also a physical change. DEFINITION: Physical change A change that can be seen or felt, but that doesn’t involve the break up of the particles in the reaction. During a physical change, the form of matter may change, but not its identity.
    [Show full text]
  • Physical and Chemical Changes of Hydrogen Peroxide Under High Pressures
    Physical and chemical changes of hydrogen peroxide under high pressures Jing-Yin Chen and Choong-Shik Yoo (PI) Washington State University, Pullman, Washington 99164 ) -1 1575 9.5% 19.6% Motivations and Objectives Phase Transitions in H2O2 Behaviors 1550 of Binary Mixtures: H2O + H2O2 1525 RamanShifts (cm Ref: H. Cynn, S.A. Sheffield & C.S. Yoo, J Chem. Phys. 110, 1999, 6836-6843 C (wt %) Raman Spectral Evidence H2O2 Structural Evidence downloading 10 30 50 70 90 5 (b) H O -I H O -II H O -I Transition 2 2 2 2 2 2 H O -II 0 10 1040 Zone 2 2 tetragonal orthorhombic 19.6% 4 GPa 3.3 c 8 c ) 9.5% -1 1000 44 b melting 6 GPa 2.6 40 3 (c) (a) 960 35 32 4 a Lattice Parameters (A) Parameters Lattice a 2 25 (GPa) P decomposition * 920 16 H O -I 2 2 Raman Shift (cmRaman Shift 16 5 1 O in H-type 2 3 GPa V=8.6% water cage 880 O in D-type O2 hydrate clathrates 2 800 1000 1200 water cage 0 1 2 /mol) 14 O 0 10 20 30 40 50 3 0 20 40 60 80 100 2 (9.5% H O ) Pressure (GPa) C (mole %) 2 2 H O -II H2O2 H O is a strong oxidizer and even explosive, and is often used as IED (cmV 2 2 2 2 12 4 D-type Ref: J.Y. Chen and C.S. Yoo, J. Chem. Phys. 132, 214501 (2010) Phase transition occurs at lower pressure3 for Intensity (a.u.) H-type Stability and behavior of H2O2 and water mixtures are not known 0 5 10 15 20 25 30 35 40 diluted samples.
    [Show full text]